Date of Award

Spring 5-15-2018

Author's School

Graduate School of Arts and Sciences

Author's Department


Degree Name

Doctor of Philosophy (PhD)

Degree Type



The present work aimed to directly test the theoretical claims about how we as human detect social exclusion using both physiological and behavioral methods across different life stages. Because feeling excluded from a group is a common human experience that starts in early childhood, this basic human need to belong or connect with others is argued to be universal and thought to have an evolutionary basis. In fact, it has been argued that the ability to detect being excluded may be present from birth and detecting exclusion occurs rapidly with little cognitive processing. Study 1 tested whether this rapid detection of exclusion is reflected in pupil dilation and how discerning this signal is of the social nature of exclusion. Study 2 tested how social exclusion detection emerges across the preschool years using both verbal and nonverbal measures.

Findings from Study 1 indicate that greater pupil dilation occurs when viewing exclusive individuals compared to inclusive individuals, regardless of whether participants were excluded by human players or non-human computerized players. Furthermore, pupil dilation occurred even when viewing third-party social exclusion, suggesting pupil dilation was sensitive to even exclusion that participants did not necessarily experience themselves. The magnitude of pupil dilation to exclusion was not correlated to self-reported distress levels or individual differences in rejection sensitivity. The present study is the first to show that social pain response — as indexed by pupil dilation — occurs even in non-social interactions and is not limited to first-hand experiences. This result supports the hypothesized “quick” and “crude” ostracism detection system: physiological arousal to exclusion appears to be independent of the social nature of exclusion. Thus, social pain from exclusion appears to reflect the high sensitivity to detect any instances of exclusion.

Findings from Study 2 indicate that that even 3-year-old children could detect social exclusion, but their ability to detect and respond to social exclusion improves with age. Strikingly, children were able to detect social exclusion occurred regardless of whether exclusion was verbally communicated (explicit) or nonverbally communicated (implicit). Furthermore, contrary to expectations from previous research on social cognitive reasoning in infancy, young children’s nonverbal responses (i.e., preferences and sharing behavior) did not necessarily reflect detection of exclusion at an earlier age than their verbal responses. Children’s preferences closely matched their verbal distinction of exclusive and inclusive agents and both preferences and verbal reasoning appeared to mature at a similar rate across development. Such finding suggests that children show remarkably early emerging ability to notice when one is left out.

Taken together, the present body of work clarified the physiological component behind ostracism detection and the developmental trajectory of social exclusion detection in early childhood. Findings from this work have important methodological implications for the field of developmental social cognition as well as practical and clinical implications of bullying and atypical social development.


English (en)

Chair and Committee

Lori Markson

Committee Members

Pascal Boyer, Rebecca Treiman, Richard Abrams, John Rohrbaugh,


Permanent URL: